Flexural Properties of Multi-Tow Structures Constructed from Glass/Polypropylene Tape under Various Manufacturing Conditions

In this study, a multi-tow structure that can provide load-bearing functionality was fabricated through a proposed consolidation process proposed using polypropylene-impregnated continuous-glass-fiber composite tape (glass/PP tape). The flexural properties of the multi-tow structure were analyzed to evaluate the influence of the processing temperature, processing speed, number of glass/PP tapes, and glass fiber content of the glass/PP tapes. The proposed process for constructing the multi-tow structure can generate straight, curved, and looped three-dimensional structures by using a multi-joint robot and instantaneous consolidation of glass/PP tapes. As the number of glass/PP tapes increased, the resin-rich area increased and the void volume fraction in the multi-tow structure increased from 2 to 5 vol%, while the flexural strength decreased. However, when the number of glass/PP tapes and processing temperature were adjusted appropriately, the flexural strength of the multi-tow structure that can be constructed at speeds 30 times faster than those of conventional pultrusion process was relatively superior. The results of a finite element analysis, confirmed that the inclusion of the proposed multi-tow structure in a bumper beam was effective in reducing deformation and absorbing the impact energy due to external loads.